cell membrane - mr walter's website · 2018-08-27 · label the cell wall and cell membrane on...
TRANSCRIPT
Hmm… If a cell needs glucose for energy, what does the glucose (needed for energy)
have to pass in order to get into the cell and to the mitochondria?
__________________________ also known as the: ______________________________
Cell Membrane: Function & Purpose
Functions:
Regulates ________________________________________________________________________
Also allows cell communication, identification and allows the ingestion and excretion of certain materials.
Life functions = ___________________________________________________________________
Helps the cell maintain _____________________________ by regulating what enters and leaves the cell.
Cell membrane only lets certain things in and out!
The cell membrane is ______________________________________ because it only lets certain
substances in and out.
Cell Membrane: Structure
What are the parts that make up the Cell Membrane?
Cell or Plasma Membrane is sometimes referred to as a _____________________________________
Made of ________________________ of Phospholipids
Phospholipid:
Polar head containing the element phosphorous
_______________________________________(Hydrophyllic)
Non-polar fatty acid tail
_________________________________ (hydrophobic)
Phospholipid Bilayer
Why is the membrane a bilayer?
Cell Membrane has more than just phospholipids…
Cell Membrane
How are things moved within a cell?
How does a cell get rid of waste and take in nutrients?
The cell membrane also ___________________________ inside it!
Help in cell ______________________________ and ____________________________ across the
membrane
Types of Membrane Proteins
1. Channel Proteins
2. Receptors
3. Glycoproteins
Membrane Proteins
1. _____________________________ (Transport Proteins): Molecules that are a little too large to pass into or
out of the cell use channel proteins to enter or leave.
2. __________________________________: Transmit information into the cell by reacting with certain
molecules. The part that sticks out has a specific shape and only molecules with the matching shape can bind
to it.
This is how some pathogens (such as viruses) attach to and enter cells!
3. _______________________________ (Glycoproteins): The name tags of the cell. Gives each cell its own
identity.
Label your Diagram!
Cell Membrane: Fluid Mosaic Model
Channel Protein Receptor Protein Fatty Acid Tail
Watery Cytoplasm Phospholipid Marker Protein
Phosphate Head
The cell membrane is a ______________________________________________ between the cell’s internal
environment and the outside environment
Fluid – Phospholipids and associated proteins move around like water in the ocean. The membrane is flexible.
Mosaic – So many different pieces make the membrane look like a mosaic or quilt.
Cell Membrane: Transport & Movement
What is transport?
The ____________________________ of material from one place to another.
There are 2 ways that material moves into and out of a cell
1. Transport that requires energy (ATP) is known as: ________________________
2. Transport that does not require energy is known as: ________________________________ or
____________________
Selectively Permeability of the Cell Membrane
Cell membrane DOES NOT let everything in and out of the cell!
Some materials cross membranes easily:
1. _________________________________________: water, oxygen, CO2, amino acids, glucose
Some materials do NOT cross membranes easily:
1. _________________________________________: Starches, proteins and other macromolecules
Hmmm….
Generally, what tells if a molecule will easily pass through a membrane?
WHY do molecules move?
1. The cell wants to maintain _________________________________
o Certain compounds enter the cell in order to maintain a stable internal environment. For example: if a
cell is low on oxygen, oxygen will move into the cell.
2. Concentration Gradient
o Difference in concentration where molecules move from areas of ________________________
_______________________________________________________________________________ to
maintain a dynamic equilibrium (homeostasis).
Dynamic Equilibrium = Homeostasis
______________________________________________________________________ back and forth across the
membrane but at an equal rate.
Small molecules pass through the cell membrane directly by squeezing through the phospholipids in the
membrane
Slightly ______________________________ cannot do this so they must use _________________
___________________
Two Types of Transport
1. Passive Transport: ____________________ required
1. Diffusion
2. Facilitated Diffusion
3. Osmosis
2. Active Transport: ___________________________
(ATP) for transport.
1. Active Transport
2. Endocytosis
3. Exocytosis
3 Types of Passive Transport
1. Diffusion
Diffusion - Movement of materials from an area of _________ concentration (more molecules in one
area) to an area of _____________ concentration (fewer molecules in an area).
Diffusion is ________________________________________________________________________ to
easily diffuse across the membrane.
2. Facilitated Diffusion
Facilitated diffusion – molecules move from areas of high to low
concentration _________________________________________
_____________________________________________________
Some molecules, such as __________________, are a little too
_____________ to pass through the membrane by simple diffusion.
These molecules need help and use __________________ _________________ to pass through the
membrane
3. Osmosis
Osmosis – Diffusion of ____________________. Water will move from areas of high to low
concentration.
Water will always move to where there is more
_____________________________________
(solute) in water.
Or, water will move from where it is more
concentrated to where it is less concentrated.
Osmosis Questions
1. Cell contains 10% salt and outside the cell contains 20% salt. Where will
water come from and go to? How much % water is in and out of the cell?
2. Cell contains 10% salt and the cell is put in distilled water. Where will
water come from and go to? How much% water is in and out of the cell?
3. Kenny was on a boat and forgot to pack water. He made a bad move and
drank salt water from the ocean. What will happen to the cells in his body?
4. Why do restaurants soak their lettuce and vegetables in water before they serve them?
To ______________________________
Which cells are at equilibrium, in salt water and in
distilled water?
A.___________________________
B.___________________________
C.___________________________
2 Types of Active Transport
Active Transport
What is used in active transport that is not used in passive transport (diffusion)?
Why would you need to use energy to transport molecules across a membrane?
1. Active Transport
Movement of a substance across a membrane _______________________________
This occurs when molecules are moving from areas of _______________________
___________________________________________________________________
Active transport occurs through special ______________________________ that
push / pull molecules into or out of the cell using energy.
Where is the concentration the highest?
How would blue diamond get into the cell?
Exocytosis
Exocytosis – type of active transport when ______________________________________________
______________________________________________________________________. Uses ATP
o Example – insulin leaves pancreatic cells by exocytosis
Vacuoles inside cell fuse / connect with the cell membrane and empty contents outside the cell
Endocytosis
Endocytosis – type of active transport where ________________ molecules, such as _______________, or large
amounts of material enter the cell. Uses ATP.
o Phagocytosis – membrane _______________________ and surrounds big molecule creating a
____________________.
Practice Problems
What happened to these plant cells?
Do Now’s & Workspace
Do Now 1
1. How is a plant cell different from an animal cell?
2. What life functions do the following cell organelles carry out?
a. Mitochondria
b. Cell membrane
c. Endoplasmic Reticulum
d. Ribosomes
3. Where are enzymes synthesized?
4. What makes one protein different from another?
DO NOW 2
Do Now 3
Name the molecule or structure: 1. Communicates messages to a cell. Found in the cell membrane.
2. Only 3 atoms big and is able to pass through a semipermeable membrane.
Compound Lipid Monosaccharide
Starch Enzyme Amino Acid
Big Molecule Small Molecule
Polysaccharide
Amino Acid
Glucose
Protein
Fatty Acid
Iodine Atom
3. Breaks down and synthesizes molecules needed by a cell.
4. Regulates the movement of molecules in and out of a cell
5. This structure allows slightly larger molecules to pass through the cell membrane.
Do Now 4
Draw arrows and show the movement of molecules.
Will the molecules even pass the semipermeable membrane? Why?
Do Now 5
Label the cell wall and cell membrane on the plant cell at equilibrium. Second, draw the plant cell when it is
placed in a salt water solution.
Do Now 6
Predict what will happen in this picture after diffusion occurs. Focus on the amount of molecules inside and outside the membrane.
I – Iodine G – Glucose
S – Starch